Much of the Earth remains unexplored

“Earth” has always been an odd choice of name for the third planet from the Sun. After all, an alien examining it through a telescope would note that two-thirds of its surface is covered not by earth at all, but by .Because humans are land-lubbing animals, most of the Earth remains under-explored. Marine biologists think the oceans might host more than 2m species of marine animals, of which they have so far catalogued perhaps a tenth. are fond of pointing out that scientists have mapped nearly all of the Martian surface, but less than a quarter of the seabed.